Selenium level and depressive symptoms in a rural elderly Chinese cohort.

BACKGROUND: Selenium is considered a protective agent against free radicals through the maintenance of better enzyme activity. The few studies examining the relationship between selenium and depression have yielded inconsistent results and none of these studies considered the role of cognitive function in this context. METHODS: A cross-sectional evaluation of 1737 rural Chinese age 65 and over from two provinces in China was conducted. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). Cognitive function was assessed using various cognitive instruments. Selenium measures were obtained from nail samples. Other information collected included demographic characteristics and medical history. Analysis of covariance models were used to identify factors associated with GDS score. RESULTS: Higher selenium levels were associated with lower GDS scores adjusting for demographic and medical conditions (p=0.0321). However, the association between selenium and depressive symptoms was no longer significant when cognitive function score was adjusted in the model (p=0.2143). CONCLUSIONS: Higher selenium level was associated with lower depressive symptoms without adjusting for cognition in this cohort. However, after cognition was adjusted in the model the association between selenium and depressive symptoms was no longer significant, suggesting that selenium's association with depressive symptoms may be primarily through its association with cognitive function.

Selenium level is associated with apoE epsilon4 in rural elderly Chinese.

OBJECTIVE: Se is an essential trace element in human nutrition associated with antioxidant activity. Previous studies on predictors of toenail Se or serum Se have mostly concentrated on demographic factors such as age and gender. The present paper examines the association between apoE genotype and Se levels in nail samples in a rural elderly Chinese cohort. DESIGN: Two thousand Chinese aged 65 years and over from four counties in China were enrolled in a cohort to study the association of Se with cognitive decline. Nail samples were collected from each participant and analysed for Se levels. Dietary Se intake was estimated from an FFQ using Se contents measured in food items collected from each village. Blood samples on filter cards were collected and analysed for apoE genotype. Mixed-effect models were constructed with nail Se level as the dependent variable and each village as the random effect, which controlled for the potential confounding effect from correlation in Se measures obtained from participants residing in the same village. RESULTS: In this elderly Chinese cohort, carriers of the apoE epsilon4 allele had significantly lower Se levels measured in nail samples than non-carriers after adjusting for other significant covariates and controlling for estimated dietary Se intake. There was no significant difference between the two genotypes on estimated Se dietary intake (P = 0.6451). CONCLUSIONS: Future studies are needed to examine the mechanism underlying the association between the apoE epsilon4 allele and Se levels, including the role of oxidative stress and that of reduced lipid metabolism in the apoE epsilon4 carriers.

[Study on distribution of endemic arsenism in China].

Drinking water and burning coal endemic arsenism as a severe disease is confirmed by National Ministry of Health in China in 1992. It is not uniform survey of the disease for the whole country from its report in 1980 in xijiang. Therefore National Ministry of Scientific and Technology in China supports to study on distribution of endemic arsenism in 21 provinces in China, so that it can know the basic distribution of endemic arsenism in China, and the data results will be a guide for the disease prevention and control. The project used environmental epidemiology study including retrospective epidemiology, present situation survey of the disease in severe areas and sampling investigation in unknown areas, collecting data of exposure population and arsenism cases. At the same time, the data of arsenic level in environment were collected, and environment samples were analyzed by standard chemical method. The both data were statistical analysis by access database and SAS procedure in computer. Through the study, it achieves the expected aim that grasps spreading distribution of drinking water arsenism and burning coal arsenism, including arsenic level in water, coal, food and air, as well as patient's condition of the disease at macroscopic. Drinking water endemic arsenism distributed in 8 provinces, 40 counties, affecting 2,343,238 peoples, among 522566 peoples expositing to the drinking water arsenic higher than 0.05 mg/L, and 7821 arsenism patients were diagnosed. Burning coal endemic arsenism spreads in 2 provinces, 8 counties, affecting 333905 peoples, 48438 peoples exposing to high arsenic of burning coal pollution, and 2402 peoples causing chronic arsenic poising by coal burning. Drinking water endemic arsenism: Nemeng, Shanxi is a severe drinking water endemic region also. Wusu city in Xinjiang is old arsenism area, which reformed drinking water to decrease arsenic, so chronic arsenic poisoning condition decreasing. Reforming drinking water measures to decreees arsenic were performed in some areas of Neimeng and Shanxi. On other hand, 1 county of Jilin and 1 county of Ningxia as drinking water arsenism areas were affirmed. 11 counties of Shanyi, 1 Banner of Nemeng, 1 city of Jilin, 1 county of Qinhai and 1 counties of Anhui province were discovered for new drinking water arsenism areas in this survey. Shunyi district of Beijing has high arsenic in drinking water. Otherwise, high arsenic content in drinking water in some areas decreased to lower than 0.05 mg/L, which including some villages of Liaoning province, Tongxing city of Zhejiang province, and Tianzhu village of Shunyi district in Beijing. Blackfoot disease related to high arsenic in drinking water in Taiwan province does not include in this study. Burning coal endemic arsenism: Guizhou province has a typical burning coal arsenism areas in China and world. Although to reform stove and decreasing arsenic pollution, but the chronic arsenic poisoning from domestic coal combustion exists, because it located high seal level and poor areas. Some new burning coal arsenism areas in Shanxi province were found, which produced air pollution and food pollution of arsenic from domestic coal combustion for cooking and heating. The paper summarizes the arsenic distribution levels in drinking water and in environment of burning coal. At the same time, preventive and control measures of endemic arsenism were provided.

[Relations between trace elements in drinking water and elderly residents' cognitive function].

The relationship between trace element levels in drinking water and cognitive function was studied for elderly residents in rural areas in China. Cognitive function was measured by a Chinese translation of the Community Screening Interview for Dementia (CSI "D"). The trace elements fluoride, calcium, selenium, aluminum, iron, zinc, cadmium, lead and arsenic contents of drinking water were determined using Chinese. National Standard Methods. A mixed effects model was used to evaluate the effect of each of the elements on cognitive function while adjusting for age, sex, and education level. Several of the elements examined had a significant effect on cognitive function when they were examined in a univariate context. However, after adjusting for other elements many of these results were not significant. There was a significant quadratic effect for calcium and a significant zinc-cadmium interaction. Cognitive function increased with calcium level to a certain point, and then decreased as calcium continued to increase. Zinc showed a positive relationship with cognitive function at low cadmium levels, but a negative relationship at high cadmium levels.

Normative data for neuropsychological tests in a rural elderly Chinese cohort.

Normative information is important for appropriate interpretation of cognitive test scores as a critical component of dementia diagnosis in the elderly population. A cross-sectional evaluation of 1826 participants aged 65 years and older from four rural counties in China was conducted using six cognitive instruments including tests of global cognitive function (the Community Screening Instrument for Dementia), memory (Word List Learning and Recall tasks from the Consortium to Establish a Registry for Alzheimer's Disease, IU Story), language (Animal Fluency Test), and executive function (IU Token). Multiple regression models adjusting for demographic variables were used to provide standardized residuals z-scores and corresponding percentile ranking for each cognitive test. In all cognitive tests older age was associated with worse test performance while exposure to education was related to better cognitive test performance. We also detected a significant gender difference with men scoring better than women and a significant gender by education interaction on two tests. The interaction indicates that gender difference in test scores was much smaller in participants with more education than those who had less or no education. These demographically adjusted, regression-based norms can be a useful tool to clinicians involved with differential diagnosis of cognitive and memory disorders in older adults in rural China.

Selenium level and cognitive function in rural elderly Chinese.

Selenium is a trace element associated with antioxidant activity and is considered to be a protective agent against free radicals through enhanced enzyme activity. Studies on selenium and cognitive function or Alzheimer's disease have yielded inconsistent results. A cross-sectional survey of 2,000 rural Chinese aged 65 years or older from two provinces in the People's Republic of China was conducted from December 2003 to May 2005 by use of the Community Screening Instrument for Dementia, the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word List Learning Test, the Indiana University Story Recall Test, the Animal Fluency Test, and the Indiana University Token Test. Over 70% of the study participants have lived in the same village since birth. Nail samples were collected and analyzed for selenium contents. Analysis-of-covariance models were used to estimate the association between quintile selenium levels measured in nail samples and cognitive test scores, with adjustment for other covariates. Lower selenium levels measured in nail samples were significantly associated with lower cognitive scores (p < 0.0087 for all tests) except the Animal Fluency Test (p = 0.4378). A dose-response effect of selenium quintiles was also seen for those significant associations. Results in this geographically stable cohort support the hypothesis that a lifelong low selenium level is associated with lower cognitive function.